It is known to provide the aforementioned end wall with a horizontal slit traversed by a towing strap which has a handgrip secured to its outer extremity and has its inner extremity attached to a spring anchored to the interior of the suitcase for tending to draw the strap in. In these known devices the spring is of the spiral kind partly wound into a coil within the suitcase. This is somewhat inconvenient since the coil, for protection, must be enclosed in a housing taking up considerable space.